The use of an etch resist ink in the production of printed circuit boards (PCB's) is known in the art. For example, a process of making PCB's by printing an image of an etch resist ink onto a substrate comprising a top layer of an electrically conductive material, is known. In a subsequent step of the process, the part of the top layer not covered by the etch resist ink is removed, by treating the substrate with an etching solution. In a later step, the image of etch resist ink is removed, yielding a PCB. The removal of the part of the top layer not covered by the etch resist is generally performed by treating the substrate with an acidic etching solution. Therefore, the etch resist ink has to be resistant to the acidic etching solution.
When preparing a PCB, it is important that the image of etch resist ink, provided on the substrate, is robust, such that the substrate may be moved between the different baths used in the etching process, without damaging the image of etch resist ink. Moving the substrate may be done using conventional transport systems, e.g. transport systems comprising a belt. The belt may damage the printed image, when contacting the substrate provided with the image of etch resist ink. Damaging of the print may result in unwanted areas of the substrate being etched, leading to disruptions in the electronic circuitry, as a result of which the PCB may not function due to an interruption in the electronic connections.
It is therefore an object of the invention to provide a hot melt inkjet ink composition that is suitable to be used as an etch resist and shows improved print robustness.